xref: /openbmc/linux/drivers/bus/mhi/host/pm.c (revision 7671f967)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (c) 2018-2020, The Linux Foundation. All rights reserved.
4  *
5  */
6 
7 #include <linux/delay.h>
8 #include <linux/device.h>
9 #include <linux/dma-direction.h>
10 #include <linux/dma-mapping.h>
11 #include <linux/interrupt.h>
12 #include <linux/list.h>
13 #include <linux/mhi.h>
14 #include <linux/module.h>
15 #include <linux/slab.h>
16 #include <linux/wait.h>
17 #include "internal.h"
18 
19 /*
20  * Not all MHI state transitions are synchronous. Transitions like Linkdown,
21  * SYS_ERR, and shutdown can happen anytime asynchronously. This function will
22  * transition to a new state only if we're allowed to.
23  *
24  * Priority increases as we go down. For instance, from any state in L0, the
25  * transition can be made to states in L1, L2 and L3. A notable exception to
26  * this rule is state DISABLE.  From DISABLE state we can only transition to
27  * POR state. Also, while in L2 state, user cannot jump back to previous
28  * L1 or L0 states.
29  *
30  * Valid transitions:
31  * L0: DISABLE <--> POR
32  *     POR <--> POR
33  *     POR -> M0 -> M2 --> M0
34  *     POR -> FW_DL_ERR
35  *     FW_DL_ERR <--> FW_DL_ERR
36  *     M0 <--> M0
37  *     M0 -> FW_DL_ERR
38  *     M0 -> M3_ENTER -> M3 -> M3_EXIT --> M0
39  * L1: SYS_ERR_DETECT -> SYS_ERR_PROCESS --> POR
40  * L2: SHUTDOWN_PROCESS -> LD_ERR_FATAL_DETECT
41  *     SHUTDOWN_PROCESS -> DISABLE
42  * L3: LD_ERR_FATAL_DETECT <--> LD_ERR_FATAL_DETECT
43  *     LD_ERR_FATAL_DETECT -> DISABLE
44  */
45 static const struct mhi_pm_transitions dev_state_transitions[] = {
46 	/* L0 States */
47 	{
48 		MHI_PM_DISABLE,
49 		MHI_PM_POR
50 	},
51 	{
52 		MHI_PM_POR,
53 		MHI_PM_POR | MHI_PM_DISABLE | MHI_PM_M0 |
54 		MHI_PM_SYS_ERR_DETECT | MHI_PM_SHUTDOWN_PROCESS |
55 		MHI_PM_LD_ERR_FATAL_DETECT | MHI_PM_FW_DL_ERR
56 	},
57 	{
58 		MHI_PM_M0,
59 		MHI_PM_M0 | MHI_PM_M2 | MHI_PM_M3_ENTER |
60 		MHI_PM_SYS_ERR_DETECT | MHI_PM_SHUTDOWN_PROCESS |
61 		MHI_PM_LD_ERR_FATAL_DETECT | MHI_PM_FW_DL_ERR
62 	},
63 	{
64 		MHI_PM_M2,
65 		MHI_PM_M0 | MHI_PM_SYS_ERR_DETECT | MHI_PM_SHUTDOWN_PROCESS |
66 		MHI_PM_LD_ERR_FATAL_DETECT
67 	},
68 	{
69 		MHI_PM_M3_ENTER,
70 		MHI_PM_M3 | MHI_PM_SYS_ERR_DETECT | MHI_PM_SHUTDOWN_PROCESS |
71 		MHI_PM_LD_ERR_FATAL_DETECT
72 	},
73 	{
74 		MHI_PM_M3,
75 		MHI_PM_M3_EXIT | MHI_PM_SYS_ERR_DETECT |
76 		MHI_PM_LD_ERR_FATAL_DETECT
77 	},
78 	{
79 		MHI_PM_M3_EXIT,
80 		MHI_PM_M0 | MHI_PM_SYS_ERR_DETECT | MHI_PM_SHUTDOWN_PROCESS |
81 		MHI_PM_LD_ERR_FATAL_DETECT
82 	},
83 	{
84 		MHI_PM_FW_DL_ERR,
85 		MHI_PM_FW_DL_ERR | MHI_PM_SYS_ERR_DETECT |
86 		MHI_PM_SHUTDOWN_PROCESS | MHI_PM_LD_ERR_FATAL_DETECT
87 	},
88 	/* L1 States */
89 	{
90 		MHI_PM_SYS_ERR_DETECT,
91 		MHI_PM_SYS_ERR_PROCESS | MHI_PM_SHUTDOWN_PROCESS |
92 		MHI_PM_LD_ERR_FATAL_DETECT
93 	},
94 	{
95 		MHI_PM_SYS_ERR_PROCESS,
96 		MHI_PM_POR | MHI_PM_SHUTDOWN_PROCESS |
97 		MHI_PM_LD_ERR_FATAL_DETECT
98 	},
99 	/* L2 States */
100 	{
101 		MHI_PM_SHUTDOWN_PROCESS,
102 		MHI_PM_DISABLE | MHI_PM_LD_ERR_FATAL_DETECT
103 	},
104 	/* L3 States */
105 	{
106 		MHI_PM_LD_ERR_FATAL_DETECT,
107 		MHI_PM_LD_ERR_FATAL_DETECT | MHI_PM_DISABLE
108 	},
109 };
110 
111 enum mhi_pm_state __must_check mhi_tryset_pm_state(struct mhi_controller *mhi_cntrl,
112 						   enum mhi_pm_state state)
113 {
114 	unsigned long cur_state = mhi_cntrl->pm_state;
115 	int index = find_last_bit(&cur_state, 32);
116 
117 	if (unlikely(index >= ARRAY_SIZE(dev_state_transitions)))
118 		return cur_state;
119 
120 	if (unlikely(dev_state_transitions[index].from_state != cur_state))
121 		return cur_state;
122 
123 	if (unlikely(!(dev_state_transitions[index].to_states & state)))
124 		return cur_state;
125 
126 	mhi_cntrl->pm_state = state;
127 	return mhi_cntrl->pm_state;
128 }
129 
130 void mhi_set_mhi_state(struct mhi_controller *mhi_cntrl, enum mhi_state state)
131 {
132 	if (state == MHI_STATE_RESET) {
133 		mhi_write_reg_field(mhi_cntrl, mhi_cntrl->regs, MHICTRL,
134 				    MHICTRL_RESET_MASK, 1);
135 	} else {
136 		mhi_write_reg_field(mhi_cntrl, mhi_cntrl->regs, MHICTRL,
137 				    MHICTRL_MHISTATE_MASK, state);
138 	}
139 }
140 
141 /* NOP for backward compatibility, host allowed to ring DB in M2 state */
142 static void mhi_toggle_dev_wake_nop(struct mhi_controller *mhi_cntrl)
143 {
144 }
145 
146 static void mhi_toggle_dev_wake(struct mhi_controller *mhi_cntrl)
147 {
148 	mhi_cntrl->wake_get(mhi_cntrl, false);
149 	mhi_cntrl->wake_put(mhi_cntrl, true);
150 }
151 
152 /* Handle device ready state transition */
153 int mhi_ready_state_transition(struct mhi_controller *mhi_cntrl)
154 {
155 	struct mhi_event *mhi_event;
156 	enum mhi_pm_state cur_state;
157 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
158 	u32 interval_us = 25000; /* poll register field every 25 milliseconds */
159 	int ret, i;
160 
161 	/* Check if device entered error state */
162 	if (MHI_PM_IN_FATAL_STATE(mhi_cntrl->pm_state)) {
163 		dev_err(dev, "Device link is not accessible\n");
164 		return -EIO;
165 	}
166 
167 	/* Wait for RESET to be cleared and READY bit to be set by the device */
168 	ret = mhi_poll_reg_field(mhi_cntrl, mhi_cntrl->regs, MHICTRL,
169 				 MHICTRL_RESET_MASK, 0, interval_us);
170 	if (ret) {
171 		dev_err(dev, "Device failed to clear MHI Reset\n");
172 		return ret;
173 	}
174 
175 	ret = mhi_poll_reg_field(mhi_cntrl, mhi_cntrl->regs, MHISTATUS,
176 				 MHISTATUS_READY_MASK, 1, interval_us);
177 	if (ret) {
178 		dev_err(dev, "Device failed to enter MHI Ready\n");
179 		return ret;
180 	}
181 
182 	dev_dbg(dev, "Device in READY State\n");
183 	write_lock_irq(&mhi_cntrl->pm_lock);
184 	cur_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_POR);
185 	mhi_cntrl->dev_state = MHI_STATE_READY;
186 	write_unlock_irq(&mhi_cntrl->pm_lock);
187 
188 	if (cur_state != MHI_PM_POR) {
189 		dev_err(dev, "Error moving to state %s from %s\n",
190 			to_mhi_pm_state_str(MHI_PM_POR),
191 			to_mhi_pm_state_str(cur_state));
192 		return -EIO;
193 	}
194 
195 	read_lock_bh(&mhi_cntrl->pm_lock);
196 	if (!MHI_REG_ACCESS_VALID(mhi_cntrl->pm_state)) {
197 		dev_err(dev, "Device registers not accessible\n");
198 		goto error_mmio;
199 	}
200 
201 	/* Configure MMIO registers */
202 	ret = mhi_init_mmio(mhi_cntrl);
203 	if (ret) {
204 		dev_err(dev, "Error configuring MMIO registers\n");
205 		goto error_mmio;
206 	}
207 
208 	/* Add elements to all SW event rings */
209 	mhi_event = mhi_cntrl->mhi_event;
210 	for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) {
211 		struct mhi_ring *ring = &mhi_event->ring;
212 
213 		/* Skip if this is an offload or HW event */
214 		if (mhi_event->offload_ev || mhi_event->hw_ring)
215 			continue;
216 
217 		ring->wp = ring->base + ring->len - ring->el_size;
218 		*ring->ctxt_wp = cpu_to_le64(ring->iommu_base + ring->len - ring->el_size);
219 		/* Update all cores */
220 		smp_wmb();
221 
222 		/* Ring the event ring db */
223 		spin_lock_irq(&mhi_event->lock);
224 		mhi_ring_er_db(mhi_event);
225 		spin_unlock_irq(&mhi_event->lock);
226 	}
227 
228 	/* Set MHI to M0 state */
229 	mhi_set_mhi_state(mhi_cntrl, MHI_STATE_M0);
230 	read_unlock_bh(&mhi_cntrl->pm_lock);
231 
232 	return 0;
233 
234 error_mmio:
235 	read_unlock_bh(&mhi_cntrl->pm_lock);
236 
237 	return -EIO;
238 }
239 
240 int mhi_pm_m0_transition(struct mhi_controller *mhi_cntrl)
241 {
242 	enum mhi_pm_state cur_state;
243 	struct mhi_chan *mhi_chan;
244 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
245 	int i;
246 
247 	write_lock_irq(&mhi_cntrl->pm_lock);
248 	mhi_cntrl->dev_state = MHI_STATE_M0;
249 	cur_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_M0);
250 	write_unlock_irq(&mhi_cntrl->pm_lock);
251 	if (unlikely(cur_state != MHI_PM_M0)) {
252 		dev_err(dev, "Unable to transition to M0 state\n");
253 		return -EIO;
254 	}
255 	mhi_cntrl->M0++;
256 
257 	/* Wake up the device */
258 	read_lock_bh(&mhi_cntrl->pm_lock);
259 	mhi_cntrl->wake_get(mhi_cntrl, true);
260 
261 	/* Ring all event rings and CMD ring only if we're in mission mode */
262 	if (MHI_IN_MISSION_MODE(mhi_cntrl->ee)) {
263 		struct mhi_event *mhi_event = mhi_cntrl->mhi_event;
264 		struct mhi_cmd *mhi_cmd =
265 			&mhi_cntrl->mhi_cmd[PRIMARY_CMD_RING];
266 
267 		for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) {
268 			if (mhi_event->offload_ev)
269 				continue;
270 
271 			spin_lock_irq(&mhi_event->lock);
272 			mhi_ring_er_db(mhi_event);
273 			spin_unlock_irq(&mhi_event->lock);
274 		}
275 
276 		/* Only ring primary cmd ring if ring is not empty */
277 		spin_lock_irq(&mhi_cmd->lock);
278 		if (mhi_cmd->ring.rp != mhi_cmd->ring.wp)
279 			mhi_ring_cmd_db(mhi_cntrl, mhi_cmd);
280 		spin_unlock_irq(&mhi_cmd->lock);
281 	}
282 
283 	/* Ring channel DB registers */
284 	mhi_chan = mhi_cntrl->mhi_chan;
285 	for (i = 0; i < mhi_cntrl->max_chan; i++, mhi_chan++) {
286 		struct mhi_ring *tre_ring = &mhi_chan->tre_ring;
287 
288 		if (mhi_chan->db_cfg.reset_req) {
289 			write_lock_irq(&mhi_chan->lock);
290 			mhi_chan->db_cfg.db_mode = true;
291 			write_unlock_irq(&mhi_chan->lock);
292 		}
293 
294 		read_lock_irq(&mhi_chan->lock);
295 
296 		/* Only ring DB if ring is not empty */
297 		if (tre_ring->base && tre_ring->wp  != tre_ring->rp)
298 			mhi_ring_chan_db(mhi_cntrl, mhi_chan);
299 		read_unlock_irq(&mhi_chan->lock);
300 	}
301 
302 	mhi_cntrl->wake_put(mhi_cntrl, false);
303 	read_unlock_bh(&mhi_cntrl->pm_lock);
304 	wake_up_all(&mhi_cntrl->state_event);
305 
306 	return 0;
307 }
308 
309 /*
310  * After receiving the MHI state change event from the device indicating the
311  * transition to M1 state, the host can transition the device to M2 state
312  * for keeping it in low power state.
313  */
314 void mhi_pm_m1_transition(struct mhi_controller *mhi_cntrl)
315 {
316 	enum mhi_pm_state state;
317 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
318 
319 	write_lock_irq(&mhi_cntrl->pm_lock);
320 	state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_M2);
321 	if (state == MHI_PM_M2) {
322 		mhi_set_mhi_state(mhi_cntrl, MHI_STATE_M2);
323 		mhi_cntrl->dev_state = MHI_STATE_M2;
324 
325 		write_unlock_irq(&mhi_cntrl->pm_lock);
326 
327 		mhi_cntrl->M2++;
328 		wake_up_all(&mhi_cntrl->state_event);
329 
330 		/* If there are any pending resources, exit M2 immediately */
331 		if (unlikely(atomic_read(&mhi_cntrl->pending_pkts) ||
332 			     atomic_read(&mhi_cntrl->dev_wake))) {
333 			dev_dbg(dev,
334 				"Exiting M2, pending_pkts: %d dev_wake: %d\n",
335 				atomic_read(&mhi_cntrl->pending_pkts),
336 				atomic_read(&mhi_cntrl->dev_wake));
337 			read_lock_bh(&mhi_cntrl->pm_lock);
338 			mhi_cntrl->wake_get(mhi_cntrl, true);
339 			mhi_cntrl->wake_put(mhi_cntrl, true);
340 			read_unlock_bh(&mhi_cntrl->pm_lock);
341 		} else {
342 			mhi_cntrl->status_cb(mhi_cntrl, MHI_CB_IDLE);
343 		}
344 	} else {
345 		write_unlock_irq(&mhi_cntrl->pm_lock);
346 	}
347 }
348 
349 /* MHI M3 completion handler */
350 int mhi_pm_m3_transition(struct mhi_controller *mhi_cntrl)
351 {
352 	enum mhi_pm_state state;
353 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
354 
355 	write_lock_irq(&mhi_cntrl->pm_lock);
356 	mhi_cntrl->dev_state = MHI_STATE_M3;
357 	state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_M3);
358 	write_unlock_irq(&mhi_cntrl->pm_lock);
359 	if (state != MHI_PM_M3) {
360 		dev_err(dev, "Unable to transition to M3 state\n");
361 		return -EIO;
362 	}
363 
364 	mhi_cntrl->M3++;
365 	wake_up_all(&mhi_cntrl->state_event);
366 
367 	return 0;
368 }
369 
370 /* Handle device Mission Mode transition */
371 static int mhi_pm_mission_mode_transition(struct mhi_controller *mhi_cntrl)
372 {
373 	struct mhi_event *mhi_event;
374 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
375 	enum mhi_ee_type ee = MHI_EE_MAX, current_ee = mhi_cntrl->ee;
376 	int i, ret;
377 
378 	dev_dbg(dev, "Processing Mission Mode transition\n");
379 
380 	write_lock_irq(&mhi_cntrl->pm_lock);
381 	if (MHI_REG_ACCESS_VALID(mhi_cntrl->pm_state))
382 		ee = mhi_get_exec_env(mhi_cntrl);
383 
384 	if (!MHI_IN_MISSION_MODE(ee)) {
385 		mhi_cntrl->pm_state = MHI_PM_LD_ERR_FATAL_DETECT;
386 		write_unlock_irq(&mhi_cntrl->pm_lock);
387 		wake_up_all(&mhi_cntrl->state_event);
388 		return -EIO;
389 	}
390 	mhi_cntrl->ee = ee;
391 	write_unlock_irq(&mhi_cntrl->pm_lock);
392 
393 	wake_up_all(&mhi_cntrl->state_event);
394 
395 	device_for_each_child(&mhi_cntrl->mhi_dev->dev, &current_ee,
396 			      mhi_destroy_device);
397 	mhi_cntrl->status_cb(mhi_cntrl, MHI_CB_EE_MISSION_MODE);
398 
399 	/* Force MHI to be in M0 state before continuing */
400 	ret = __mhi_device_get_sync(mhi_cntrl);
401 	if (ret)
402 		return ret;
403 
404 	read_lock_bh(&mhi_cntrl->pm_lock);
405 
406 	if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {
407 		ret = -EIO;
408 		goto error_mission_mode;
409 	}
410 
411 	/* Add elements to all HW event rings */
412 	mhi_event = mhi_cntrl->mhi_event;
413 	for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) {
414 		struct mhi_ring *ring = &mhi_event->ring;
415 
416 		if (mhi_event->offload_ev || !mhi_event->hw_ring)
417 			continue;
418 
419 		ring->wp = ring->base + ring->len - ring->el_size;
420 		*ring->ctxt_wp = cpu_to_le64(ring->iommu_base + ring->len - ring->el_size);
421 		/* Update to all cores */
422 		smp_wmb();
423 
424 		spin_lock_irq(&mhi_event->lock);
425 		if (MHI_DB_ACCESS_VALID(mhi_cntrl))
426 			mhi_ring_er_db(mhi_event);
427 		spin_unlock_irq(&mhi_event->lock);
428 	}
429 
430 	read_unlock_bh(&mhi_cntrl->pm_lock);
431 
432 	/*
433 	 * The MHI devices are only created when the client device switches its
434 	 * Execution Environment (EE) to either SBL or AMSS states
435 	 */
436 	mhi_create_devices(mhi_cntrl);
437 
438 	read_lock_bh(&mhi_cntrl->pm_lock);
439 
440 error_mission_mode:
441 	mhi_cntrl->wake_put(mhi_cntrl, false);
442 	read_unlock_bh(&mhi_cntrl->pm_lock);
443 
444 	return ret;
445 }
446 
447 /* Handle shutdown transitions */
448 static void mhi_pm_disable_transition(struct mhi_controller *mhi_cntrl)
449 {
450 	enum mhi_pm_state cur_state;
451 	struct mhi_event *mhi_event;
452 	struct mhi_cmd_ctxt *cmd_ctxt;
453 	struct mhi_cmd *mhi_cmd;
454 	struct mhi_event_ctxt *er_ctxt;
455 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
456 	int ret, i;
457 
458 	dev_dbg(dev, "Processing disable transition with PM state: %s\n",
459 		to_mhi_pm_state_str(mhi_cntrl->pm_state));
460 
461 	mutex_lock(&mhi_cntrl->pm_mutex);
462 
463 	/* Trigger MHI RESET so that the device will not access host memory */
464 	if (!MHI_PM_IN_FATAL_STATE(mhi_cntrl->pm_state)) {
465 		dev_dbg(dev, "Triggering MHI Reset in device\n");
466 		mhi_set_mhi_state(mhi_cntrl, MHI_STATE_RESET);
467 
468 		/* Wait for the reset bit to be cleared by the device */
469 		ret = mhi_poll_reg_field(mhi_cntrl, mhi_cntrl->regs, MHICTRL,
470 				 MHICTRL_RESET_MASK, 0, 25000);
471 		if (ret)
472 			dev_err(dev, "Device failed to clear MHI Reset\n");
473 
474 		/*
475 		 * Device will clear BHI_INTVEC as a part of RESET processing,
476 		 * hence re-program it
477 		 */
478 		mhi_write_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_INTVEC, 0);
479 	}
480 
481 	dev_dbg(dev,
482 		 "Waiting for all pending event ring processing to complete\n");
483 	mhi_event = mhi_cntrl->mhi_event;
484 	for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) {
485 		if (mhi_event->offload_ev)
486 			continue;
487 		free_irq(mhi_cntrl->irq[mhi_event->irq], mhi_event);
488 		tasklet_kill(&mhi_event->task);
489 	}
490 
491 	/* Release lock and wait for all pending threads to complete */
492 	mutex_unlock(&mhi_cntrl->pm_mutex);
493 	dev_dbg(dev, "Waiting for all pending threads to complete\n");
494 	wake_up_all(&mhi_cntrl->state_event);
495 
496 	dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
497 	device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device);
498 
499 	mutex_lock(&mhi_cntrl->pm_mutex);
500 
501 	WARN_ON(atomic_read(&mhi_cntrl->dev_wake));
502 	WARN_ON(atomic_read(&mhi_cntrl->pending_pkts));
503 
504 	/* Reset the ev rings and cmd rings */
505 	dev_dbg(dev, "Resetting EV CTXT and CMD CTXT\n");
506 	mhi_cmd = mhi_cntrl->mhi_cmd;
507 	cmd_ctxt = mhi_cntrl->mhi_ctxt->cmd_ctxt;
508 	for (i = 0; i < NR_OF_CMD_RINGS; i++, mhi_cmd++, cmd_ctxt++) {
509 		struct mhi_ring *ring = &mhi_cmd->ring;
510 
511 		ring->rp = ring->base;
512 		ring->wp = ring->base;
513 		cmd_ctxt->rp = cmd_ctxt->rbase;
514 		cmd_ctxt->wp = cmd_ctxt->rbase;
515 	}
516 
517 	mhi_event = mhi_cntrl->mhi_event;
518 	er_ctxt = mhi_cntrl->mhi_ctxt->er_ctxt;
519 	for (i = 0; i < mhi_cntrl->total_ev_rings; i++, er_ctxt++,
520 		     mhi_event++) {
521 		struct mhi_ring *ring = &mhi_event->ring;
522 
523 		/* Skip offload events */
524 		if (mhi_event->offload_ev)
525 			continue;
526 
527 		ring->rp = ring->base;
528 		ring->wp = ring->base;
529 		er_ctxt->rp = er_ctxt->rbase;
530 		er_ctxt->wp = er_ctxt->rbase;
531 	}
532 
533 	/* Move to disable state */
534 	write_lock_irq(&mhi_cntrl->pm_lock);
535 	cur_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_DISABLE);
536 	write_unlock_irq(&mhi_cntrl->pm_lock);
537 	if (unlikely(cur_state != MHI_PM_DISABLE))
538 		dev_err(dev, "Error moving from PM state: %s to: %s\n",
539 			to_mhi_pm_state_str(cur_state),
540 			to_mhi_pm_state_str(MHI_PM_DISABLE));
541 
542 	dev_dbg(dev, "Exiting with PM state: %s, MHI state: %s\n",
543 		to_mhi_pm_state_str(mhi_cntrl->pm_state),
544 		mhi_state_str(mhi_cntrl->dev_state));
545 
546 	mutex_unlock(&mhi_cntrl->pm_mutex);
547 }
548 
549 /* Handle system error transitions */
550 static void mhi_pm_sys_error_transition(struct mhi_controller *mhi_cntrl)
551 {
552 	enum mhi_pm_state cur_state, prev_state;
553 	enum dev_st_transition next_state;
554 	struct mhi_event *mhi_event;
555 	struct mhi_cmd_ctxt *cmd_ctxt;
556 	struct mhi_cmd *mhi_cmd;
557 	struct mhi_event_ctxt *er_ctxt;
558 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
559 	int ret, i;
560 
561 	dev_dbg(dev, "Transitioning from PM state: %s to: %s\n",
562 		to_mhi_pm_state_str(mhi_cntrl->pm_state),
563 		to_mhi_pm_state_str(MHI_PM_SYS_ERR_PROCESS));
564 
565 	/* We must notify MHI control driver so it can clean up first */
566 	mhi_cntrl->status_cb(mhi_cntrl, MHI_CB_SYS_ERROR);
567 
568 	mutex_lock(&mhi_cntrl->pm_mutex);
569 	write_lock_irq(&mhi_cntrl->pm_lock);
570 	prev_state = mhi_cntrl->pm_state;
571 	cur_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_SYS_ERR_PROCESS);
572 	write_unlock_irq(&mhi_cntrl->pm_lock);
573 
574 	if (cur_state != MHI_PM_SYS_ERR_PROCESS) {
575 		dev_err(dev, "Failed to transition from PM state: %s to: %s\n",
576 			to_mhi_pm_state_str(cur_state),
577 			to_mhi_pm_state_str(MHI_PM_SYS_ERR_PROCESS));
578 		goto exit_sys_error_transition;
579 	}
580 
581 	mhi_cntrl->ee = MHI_EE_DISABLE_TRANSITION;
582 	mhi_cntrl->dev_state = MHI_STATE_RESET;
583 
584 	/* Wake up threads waiting for state transition */
585 	wake_up_all(&mhi_cntrl->state_event);
586 
587 	/* Trigger MHI RESET so that the device will not access host memory */
588 	if (MHI_REG_ACCESS_VALID(prev_state)) {
589 		u32 in_reset = -1;
590 		unsigned long timeout = msecs_to_jiffies(mhi_cntrl->timeout_ms);
591 
592 		dev_dbg(dev, "Triggering MHI Reset in device\n");
593 		mhi_set_mhi_state(mhi_cntrl, MHI_STATE_RESET);
594 
595 		/* Wait for the reset bit to be cleared by the device */
596 		ret = wait_event_timeout(mhi_cntrl->state_event,
597 					 mhi_read_reg_field(mhi_cntrl,
598 							    mhi_cntrl->regs,
599 							    MHICTRL,
600 							    MHICTRL_RESET_MASK,
601 							    &in_reset) ||
602 					!in_reset, timeout);
603 		if (!ret || in_reset) {
604 			dev_err(dev, "Device failed to exit MHI Reset state\n");
605 			goto exit_sys_error_transition;
606 		}
607 
608 		/*
609 		 * Device will clear BHI_INTVEC as a part of RESET processing,
610 		 * hence re-program it
611 		 */
612 		mhi_write_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_INTVEC, 0);
613 	}
614 
615 	dev_dbg(dev,
616 		"Waiting for all pending event ring processing to complete\n");
617 	mhi_event = mhi_cntrl->mhi_event;
618 	for (i = 0; i < mhi_cntrl->total_ev_rings; i++, mhi_event++) {
619 		if (mhi_event->offload_ev)
620 			continue;
621 		tasklet_kill(&mhi_event->task);
622 	}
623 
624 	/* Release lock and wait for all pending threads to complete */
625 	mutex_unlock(&mhi_cntrl->pm_mutex);
626 	dev_dbg(dev, "Waiting for all pending threads to complete\n");
627 	wake_up_all(&mhi_cntrl->state_event);
628 
629 	dev_dbg(dev, "Reset all active channels and remove MHI devices\n");
630 	device_for_each_child(&mhi_cntrl->mhi_dev->dev, NULL, mhi_destroy_device);
631 
632 	mutex_lock(&mhi_cntrl->pm_mutex);
633 
634 	WARN_ON(atomic_read(&mhi_cntrl->dev_wake));
635 	WARN_ON(atomic_read(&mhi_cntrl->pending_pkts));
636 
637 	/* Reset the ev rings and cmd rings */
638 	dev_dbg(dev, "Resetting EV CTXT and CMD CTXT\n");
639 	mhi_cmd = mhi_cntrl->mhi_cmd;
640 	cmd_ctxt = mhi_cntrl->mhi_ctxt->cmd_ctxt;
641 	for (i = 0; i < NR_OF_CMD_RINGS; i++, mhi_cmd++, cmd_ctxt++) {
642 		struct mhi_ring *ring = &mhi_cmd->ring;
643 
644 		ring->rp = ring->base;
645 		ring->wp = ring->base;
646 		cmd_ctxt->rp = cmd_ctxt->rbase;
647 		cmd_ctxt->wp = cmd_ctxt->rbase;
648 	}
649 
650 	mhi_event = mhi_cntrl->mhi_event;
651 	er_ctxt = mhi_cntrl->mhi_ctxt->er_ctxt;
652 	for (i = 0; i < mhi_cntrl->total_ev_rings; i++, er_ctxt++,
653 	     mhi_event++) {
654 		struct mhi_ring *ring = &mhi_event->ring;
655 
656 		/* Skip offload events */
657 		if (mhi_event->offload_ev)
658 			continue;
659 
660 		ring->rp = ring->base;
661 		ring->wp = ring->base;
662 		er_ctxt->rp = er_ctxt->rbase;
663 		er_ctxt->wp = er_ctxt->rbase;
664 	}
665 
666 	/* Transition to next state */
667 	if (MHI_IN_PBL(mhi_get_exec_env(mhi_cntrl))) {
668 		write_lock_irq(&mhi_cntrl->pm_lock);
669 		cur_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_POR);
670 		write_unlock_irq(&mhi_cntrl->pm_lock);
671 		if (cur_state != MHI_PM_POR) {
672 			dev_err(dev, "Error moving to state %s from %s\n",
673 				to_mhi_pm_state_str(MHI_PM_POR),
674 				to_mhi_pm_state_str(cur_state));
675 			goto exit_sys_error_transition;
676 		}
677 		next_state = DEV_ST_TRANSITION_PBL;
678 	} else {
679 		next_state = DEV_ST_TRANSITION_READY;
680 	}
681 
682 	mhi_queue_state_transition(mhi_cntrl, next_state);
683 
684 exit_sys_error_transition:
685 	dev_dbg(dev, "Exiting with PM state: %s, MHI state: %s\n",
686 		to_mhi_pm_state_str(mhi_cntrl->pm_state),
687 		mhi_state_str(mhi_cntrl->dev_state));
688 
689 	mutex_unlock(&mhi_cntrl->pm_mutex);
690 }
691 
692 /* Queue a new work item and schedule work */
693 int mhi_queue_state_transition(struct mhi_controller *mhi_cntrl,
694 			       enum dev_st_transition state)
695 {
696 	struct state_transition *item = kmalloc(sizeof(*item), GFP_ATOMIC);
697 	unsigned long flags;
698 
699 	if (!item)
700 		return -ENOMEM;
701 
702 	item->state = state;
703 	spin_lock_irqsave(&mhi_cntrl->transition_lock, flags);
704 	list_add_tail(&item->node, &mhi_cntrl->transition_list);
705 	spin_unlock_irqrestore(&mhi_cntrl->transition_lock, flags);
706 
707 	queue_work(mhi_cntrl->hiprio_wq, &mhi_cntrl->st_worker);
708 
709 	return 0;
710 }
711 
712 /* SYS_ERR worker */
713 void mhi_pm_sys_err_handler(struct mhi_controller *mhi_cntrl)
714 {
715 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
716 
717 	/* skip if controller supports RDDM */
718 	if (mhi_cntrl->rddm_image) {
719 		dev_dbg(dev, "Controller supports RDDM, skip SYS_ERROR\n");
720 		return;
721 	}
722 
723 	mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_SYS_ERR);
724 }
725 
726 /* Device State Transition worker */
727 void mhi_pm_st_worker(struct work_struct *work)
728 {
729 	struct state_transition *itr, *tmp;
730 	LIST_HEAD(head);
731 	struct mhi_controller *mhi_cntrl = container_of(work,
732 							struct mhi_controller,
733 							st_worker);
734 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
735 
736 	spin_lock_irq(&mhi_cntrl->transition_lock);
737 	list_splice_tail_init(&mhi_cntrl->transition_list, &head);
738 	spin_unlock_irq(&mhi_cntrl->transition_lock);
739 
740 	list_for_each_entry_safe(itr, tmp, &head, node) {
741 		list_del(&itr->node);
742 		dev_dbg(dev, "Handling state transition: %s\n",
743 			TO_DEV_STATE_TRANS_STR(itr->state));
744 
745 		switch (itr->state) {
746 		case DEV_ST_TRANSITION_PBL:
747 			write_lock_irq(&mhi_cntrl->pm_lock);
748 			if (MHI_REG_ACCESS_VALID(mhi_cntrl->pm_state))
749 				mhi_cntrl->ee = mhi_get_exec_env(mhi_cntrl);
750 			write_unlock_irq(&mhi_cntrl->pm_lock);
751 			mhi_fw_load_handler(mhi_cntrl);
752 			break;
753 		case DEV_ST_TRANSITION_SBL:
754 			write_lock_irq(&mhi_cntrl->pm_lock);
755 			mhi_cntrl->ee = MHI_EE_SBL;
756 			write_unlock_irq(&mhi_cntrl->pm_lock);
757 			/*
758 			 * The MHI devices are only created when the client
759 			 * device switches its Execution Environment (EE) to
760 			 * either SBL or AMSS states
761 			 */
762 			mhi_create_devices(mhi_cntrl);
763 			if (mhi_cntrl->fbc_download)
764 				mhi_download_amss_image(mhi_cntrl);
765 			break;
766 		case DEV_ST_TRANSITION_MISSION_MODE:
767 			mhi_pm_mission_mode_transition(mhi_cntrl);
768 			break;
769 		case DEV_ST_TRANSITION_FP:
770 			write_lock_irq(&mhi_cntrl->pm_lock);
771 			mhi_cntrl->ee = MHI_EE_FP;
772 			write_unlock_irq(&mhi_cntrl->pm_lock);
773 			mhi_create_devices(mhi_cntrl);
774 			break;
775 		case DEV_ST_TRANSITION_READY:
776 			mhi_ready_state_transition(mhi_cntrl);
777 			break;
778 		case DEV_ST_TRANSITION_SYS_ERR:
779 			mhi_pm_sys_error_transition(mhi_cntrl);
780 			break;
781 		case DEV_ST_TRANSITION_DISABLE:
782 			mhi_pm_disable_transition(mhi_cntrl);
783 			break;
784 		default:
785 			break;
786 		}
787 		kfree(itr);
788 	}
789 }
790 
791 int mhi_pm_suspend(struct mhi_controller *mhi_cntrl)
792 {
793 	struct mhi_chan *itr, *tmp;
794 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
795 	enum mhi_pm_state new_state;
796 	int ret;
797 
798 	if (mhi_cntrl->pm_state == MHI_PM_DISABLE)
799 		return -EINVAL;
800 
801 	if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state))
802 		return -EIO;
803 
804 	/* Return busy if there are any pending resources */
805 	if (atomic_read(&mhi_cntrl->dev_wake) ||
806 	    atomic_read(&mhi_cntrl->pending_pkts))
807 		return -EBUSY;
808 
809 	/* Take MHI out of M2 state */
810 	read_lock_bh(&mhi_cntrl->pm_lock);
811 	mhi_cntrl->wake_get(mhi_cntrl, false);
812 	read_unlock_bh(&mhi_cntrl->pm_lock);
813 
814 	ret = wait_event_timeout(mhi_cntrl->state_event,
815 				 mhi_cntrl->dev_state == MHI_STATE_M0 ||
816 				 mhi_cntrl->dev_state == MHI_STATE_M1 ||
817 				 MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state),
818 				 msecs_to_jiffies(mhi_cntrl->timeout_ms));
819 
820 	read_lock_bh(&mhi_cntrl->pm_lock);
821 	mhi_cntrl->wake_put(mhi_cntrl, false);
822 	read_unlock_bh(&mhi_cntrl->pm_lock);
823 
824 	if (!ret || MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {
825 		dev_err(dev,
826 			"Could not enter M0/M1 state");
827 		return -EIO;
828 	}
829 
830 	write_lock_irq(&mhi_cntrl->pm_lock);
831 
832 	if (atomic_read(&mhi_cntrl->dev_wake) ||
833 	    atomic_read(&mhi_cntrl->pending_pkts)) {
834 		write_unlock_irq(&mhi_cntrl->pm_lock);
835 		return -EBUSY;
836 	}
837 
838 	dev_dbg(dev, "Allowing M3 transition\n");
839 	new_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_M3_ENTER);
840 	if (new_state != MHI_PM_M3_ENTER) {
841 		write_unlock_irq(&mhi_cntrl->pm_lock);
842 		dev_err(dev,
843 			"Error setting to PM state: %s from: %s\n",
844 			to_mhi_pm_state_str(MHI_PM_M3_ENTER),
845 			to_mhi_pm_state_str(mhi_cntrl->pm_state));
846 		return -EIO;
847 	}
848 
849 	/* Set MHI to M3 and wait for completion */
850 	mhi_set_mhi_state(mhi_cntrl, MHI_STATE_M3);
851 	write_unlock_irq(&mhi_cntrl->pm_lock);
852 	dev_dbg(dev, "Waiting for M3 completion\n");
853 
854 	ret = wait_event_timeout(mhi_cntrl->state_event,
855 				 mhi_cntrl->dev_state == MHI_STATE_M3 ||
856 				 MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state),
857 				 msecs_to_jiffies(mhi_cntrl->timeout_ms));
858 
859 	if (!ret || MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {
860 		dev_err(dev,
861 			"Did not enter M3 state, MHI state: %s, PM state: %s\n",
862 			mhi_state_str(mhi_cntrl->dev_state),
863 			to_mhi_pm_state_str(mhi_cntrl->pm_state));
864 		return -EIO;
865 	}
866 
867 	/* Notify clients about entering LPM */
868 	list_for_each_entry_safe(itr, tmp, &mhi_cntrl->lpm_chans, node) {
869 		mutex_lock(&itr->mutex);
870 		if (itr->mhi_dev)
871 			mhi_notify(itr->mhi_dev, MHI_CB_LPM_ENTER);
872 		mutex_unlock(&itr->mutex);
873 	}
874 
875 	return 0;
876 }
877 EXPORT_SYMBOL_GPL(mhi_pm_suspend);
878 
879 static int __mhi_pm_resume(struct mhi_controller *mhi_cntrl, bool force)
880 {
881 	struct mhi_chan *itr, *tmp;
882 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
883 	enum mhi_pm_state cur_state;
884 	int ret;
885 
886 	dev_dbg(dev, "Entered with PM state: %s, MHI state: %s\n",
887 		to_mhi_pm_state_str(mhi_cntrl->pm_state),
888 		mhi_state_str(mhi_cntrl->dev_state));
889 
890 	if (mhi_cntrl->pm_state == MHI_PM_DISABLE)
891 		return 0;
892 
893 	if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state))
894 		return -EIO;
895 
896 	if (mhi_get_mhi_state(mhi_cntrl) != MHI_STATE_M3) {
897 		dev_warn(dev, "Resuming from non M3 state (%s)\n",
898 			 mhi_state_str(mhi_get_mhi_state(mhi_cntrl)));
899 		if (!force)
900 			return -EINVAL;
901 	}
902 
903 	/* Notify clients about exiting LPM */
904 	list_for_each_entry_safe(itr, tmp, &mhi_cntrl->lpm_chans, node) {
905 		mutex_lock(&itr->mutex);
906 		if (itr->mhi_dev)
907 			mhi_notify(itr->mhi_dev, MHI_CB_LPM_EXIT);
908 		mutex_unlock(&itr->mutex);
909 	}
910 
911 	write_lock_irq(&mhi_cntrl->pm_lock);
912 	cur_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_M3_EXIT);
913 	if (cur_state != MHI_PM_M3_EXIT) {
914 		write_unlock_irq(&mhi_cntrl->pm_lock);
915 		dev_info(dev,
916 			 "Error setting to PM state: %s from: %s\n",
917 			 to_mhi_pm_state_str(MHI_PM_M3_EXIT),
918 			 to_mhi_pm_state_str(mhi_cntrl->pm_state));
919 		return -EIO;
920 	}
921 
922 	/* Set MHI to M0 and wait for completion */
923 	mhi_set_mhi_state(mhi_cntrl, MHI_STATE_M0);
924 	write_unlock_irq(&mhi_cntrl->pm_lock);
925 
926 	ret = wait_event_timeout(mhi_cntrl->state_event,
927 				 mhi_cntrl->dev_state == MHI_STATE_M0 ||
928 				 mhi_cntrl->dev_state == MHI_STATE_M2 ||
929 				 MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state),
930 				 msecs_to_jiffies(mhi_cntrl->timeout_ms));
931 
932 	if (!ret || MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {
933 		dev_err(dev,
934 			"Did not enter M0 state, MHI state: %s, PM state: %s\n",
935 			mhi_state_str(mhi_cntrl->dev_state),
936 			to_mhi_pm_state_str(mhi_cntrl->pm_state));
937 		return -EIO;
938 	}
939 
940 	return 0;
941 }
942 
943 int mhi_pm_resume(struct mhi_controller *mhi_cntrl)
944 {
945 	return __mhi_pm_resume(mhi_cntrl, false);
946 }
947 EXPORT_SYMBOL_GPL(mhi_pm_resume);
948 
949 int mhi_pm_resume_force(struct mhi_controller *mhi_cntrl)
950 {
951 	return __mhi_pm_resume(mhi_cntrl, true);
952 }
953 EXPORT_SYMBOL_GPL(mhi_pm_resume_force);
954 
955 int __mhi_device_get_sync(struct mhi_controller *mhi_cntrl)
956 {
957 	int ret;
958 
959 	/* Wake up the device */
960 	read_lock_bh(&mhi_cntrl->pm_lock);
961 	if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {
962 		read_unlock_bh(&mhi_cntrl->pm_lock);
963 		return -EIO;
964 	}
965 	mhi_cntrl->wake_get(mhi_cntrl, true);
966 	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state))
967 		mhi_trigger_resume(mhi_cntrl);
968 	read_unlock_bh(&mhi_cntrl->pm_lock);
969 
970 	ret = wait_event_timeout(mhi_cntrl->state_event,
971 				 mhi_cntrl->pm_state == MHI_PM_M0 ||
972 				 MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state),
973 				 msecs_to_jiffies(mhi_cntrl->timeout_ms));
974 
975 	if (!ret || MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state)) {
976 		read_lock_bh(&mhi_cntrl->pm_lock);
977 		mhi_cntrl->wake_put(mhi_cntrl, false);
978 		read_unlock_bh(&mhi_cntrl->pm_lock);
979 		return -EIO;
980 	}
981 
982 	return 0;
983 }
984 
985 /* Assert device wake db */
986 static void mhi_assert_dev_wake(struct mhi_controller *mhi_cntrl, bool force)
987 {
988 	unsigned long flags;
989 
990 	/*
991 	 * If force flag is set, then increment the wake count value and
992 	 * ring wake db
993 	 */
994 	if (unlikely(force)) {
995 		spin_lock_irqsave(&mhi_cntrl->wlock, flags);
996 		atomic_inc(&mhi_cntrl->dev_wake);
997 		if (MHI_WAKE_DB_FORCE_SET_VALID(mhi_cntrl->pm_state) &&
998 		    !mhi_cntrl->wake_set) {
999 			mhi_write_db(mhi_cntrl, mhi_cntrl->wake_db, 1);
1000 			mhi_cntrl->wake_set = true;
1001 		}
1002 		spin_unlock_irqrestore(&mhi_cntrl->wlock, flags);
1003 	} else {
1004 		/*
1005 		 * If resources are already requested, then just increment
1006 		 * the wake count value and return
1007 		 */
1008 		if (likely(atomic_add_unless(&mhi_cntrl->dev_wake, 1, 0)))
1009 			return;
1010 
1011 		spin_lock_irqsave(&mhi_cntrl->wlock, flags);
1012 		if ((atomic_inc_return(&mhi_cntrl->dev_wake) == 1) &&
1013 		    MHI_WAKE_DB_SET_VALID(mhi_cntrl->pm_state) &&
1014 		    !mhi_cntrl->wake_set) {
1015 			mhi_write_db(mhi_cntrl, mhi_cntrl->wake_db, 1);
1016 			mhi_cntrl->wake_set = true;
1017 		}
1018 		spin_unlock_irqrestore(&mhi_cntrl->wlock, flags);
1019 	}
1020 }
1021 
1022 /* De-assert device wake db */
1023 static void mhi_deassert_dev_wake(struct mhi_controller *mhi_cntrl,
1024 				  bool override)
1025 {
1026 	unsigned long flags;
1027 
1028 	/*
1029 	 * Only continue if there is a single resource, else just decrement
1030 	 * and return
1031 	 */
1032 	if (likely(atomic_add_unless(&mhi_cntrl->dev_wake, -1, 1)))
1033 		return;
1034 
1035 	spin_lock_irqsave(&mhi_cntrl->wlock, flags);
1036 	if ((atomic_dec_return(&mhi_cntrl->dev_wake) == 0) &&
1037 	    MHI_WAKE_DB_CLEAR_VALID(mhi_cntrl->pm_state) && !override &&
1038 	    mhi_cntrl->wake_set) {
1039 		mhi_write_db(mhi_cntrl, mhi_cntrl->wake_db, 0);
1040 		mhi_cntrl->wake_set = false;
1041 	}
1042 	spin_unlock_irqrestore(&mhi_cntrl->wlock, flags);
1043 }
1044 
1045 int mhi_async_power_up(struct mhi_controller *mhi_cntrl)
1046 {
1047 	enum mhi_state state;
1048 	enum mhi_ee_type current_ee;
1049 	enum dev_st_transition next_state;
1050 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
1051 	u32 interval_us = 25000; /* poll register field every 25 milliseconds */
1052 	int ret;
1053 
1054 	dev_info(dev, "Requested to power ON\n");
1055 
1056 	/* Supply default wake routines if not provided by controller driver */
1057 	if (!mhi_cntrl->wake_get || !mhi_cntrl->wake_put ||
1058 	    !mhi_cntrl->wake_toggle) {
1059 		mhi_cntrl->wake_get = mhi_assert_dev_wake;
1060 		mhi_cntrl->wake_put = mhi_deassert_dev_wake;
1061 		mhi_cntrl->wake_toggle = (mhi_cntrl->db_access & MHI_PM_M2) ?
1062 			mhi_toggle_dev_wake_nop : mhi_toggle_dev_wake;
1063 	}
1064 
1065 	mutex_lock(&mhi_cntrl->pm_mutex);
1066 	mhi_cntrl->pm_state = MHI_PM_DISABLE;
1067 
1068 	/* Setup BHI INTVEC */
1069 	write_lock_irq(&mhi_cntrl->pm_lock);
1070 	mhi_write_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_INTVEC, 0);
1071 	mhi_cntrl->pm_state = MHI_PM_POR;
1072 	mhi_cntrl->ee = MHI_EE_MAX;
1073 	current_ee = mhi_get_exec_env(mhi_cntrl);
1074 	write_unlock_irq(&mhi_cntrl->pm_lock);
1075 
1076 	/* Confirm that the device is in valid exec env */
1077 	if (!MHI_POWER_UP_CAPABLE(current_ee)) {
1078 		dev_err(dev, "%s is not a valid EE for power on\n",
1079 			TO_MHI_EXEC_STR(current_ee));
1080 		ret = -EIO;
1081 		goto error_exit;
1082 	}
1083 
1084 	state = mhi_get_mhi_state(mhi_cntrl);
1085 	dev_dbg(dev, "Attempting power on with EE: %s, state: %s\n",
1086 		TO_MHI_EXEC_STR(current_ee), mhi_state_str(state));
1087 
1088 	if (state == MHI_STATE_SYS_ERR) {
1089 		mhi_set_mhi_state(mhi_cntrl, MHI_STATE_RESET);
1090 		ret = mhi_poll_reg_field(mhi_cntrl, mhi_cntrl->regs, MHICTRL,
1091 				 MHICTRL_RESET_MASK, 0, interval_us);
1092 		if (ret) {
1093 			dev_info(dev, "Failed to reset MHI due to syserr state\n");
1094 			goto error_exit;
1095 		}
1096 
1097 		/*
1098 		 * device cleares INTVEC as part of RESET processing,
1099 		 * re-program it
1100 		 */
1101 		mhi_write_reg(mhi_cntrl, mhi_cntrl->bhi, BHI_INTVEC, 0);
1102 	}
1103 
1104 	ret = mhi_init_irq_setup(mhi_cntrl);
1105 	if (ret)
1106 		goto error_exit;
1107 
1108 	/* Transition to next state */
1109 	next_state = MHI_IN_PBL(current_ee) ?
1110 		DEV_ST_TRANSITION_PBL : DEV_ST_TRANSITION_READY;
1111 
1112 	mhi_queue_state_transition(mhi_cntrl, next_state);
1113 
1114 	mutex_unlock(&mhi_cntrl->pm_mutex);
1115 
1116 	dev_info(dev, "Power on setup success\n");
1117 
1118 	return 0;
1119 
1120 error_exit:
1121 	mhi_cntrl->pm_state = MHI_PM_DISABLE;
1122 	mutex_unlock(&mhi_cntrl->pm_mutex);
1123 
1124 	return ret;
1125 }
1126 EXPORT_SYMBOL_GPL(mhi_async_power_up);
1127 
1128 void mhi_power_down(struct mhi_controller *mhi_cntrl, bool graceful)
1129 {
1130 	enum mhi_pm_state cur_state, transition_state;
1131 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
1132 
1133 	mutex_lock(&mhi_cntrl->pm_mutex);
1134 	write_lock_irq(&mhi_cntrl->pm_lock);
1135 	cur_state = mhi_cntrl->pm_state;
1136 	if (cur_state == MHI_PM_DISABLE) {
1137 		write_unlock_irq(&mhi_cntrl->pm_lock);
1138 		mutex_unlock(&mhi_cntrl->pm_mutex);
1139 		return; /* Already powered down */
1140 	}
1141 
1142 	/* If it's not a graceful shutdown, force MHI to linkdown state */
1143 	transition_state = (graceful) ? MHI_PM_SHUTDOWN_PROCESS :
1144 			   MHI_PM_LD_ERR_FATAL_DETECT;
1145 
1146 	cur_state = mhi_tryset_pm_state(mhi_cntrl, transition_state);
1147 	if (cur_state != transition_state) {
1148 		dev_err(dev, "Failed to move to state: %s from: %s\n",
1149 			to_mhi_pm_state_str(transition_state),
1150 			to_mhi_pm_state_str(mhi_cntrl->pm_state));
1151 		/* Force link down or error fatal detected state */
1152 		mhi_cntrl->pm_state = MHI_PM_LD_ERR_FATAL_DETECT;
1153 	}
1154 
1155 	/* mark device inactive to avoid any further host processing */
1156 	mhi_cntrl->ee = MHI_EE_DISABLE_TRANSITION;
1157 	mhi_cntrl->dev_state = MHI_STATE_RESET;
1158 
1159 	wake_up_all(&mhi_cntrl->state_event);
1160 
1161 	write_unlock_irq(&mhi_cntrl->pm_lock);
1162 	mutex_unlock(&mhi_cntrl->pm_mutex);
1163 
1164 	mhi_queue_state_transition(mhi_cntrl, DEV_ST_TRANSITION_DISABLE);
1165 
1166 	/* Wait for shutdown to complete */
1167 	flush_work(&mhi_cntrl->st_worker);
1168 
1169 	free_irq(mhi_cntrl->irq[0], mhi_cntrl);
1170 }
1171 EXPORT_SYMBOL_GPL(mhi_power_down);
1172 
1173 int mhi_sync_power_up(struct mhi_controller *mhi_cntrl)
1174 {
1175 	int ret = mhi_async_power_up(mhi_cntrl);
1176 
1177 	if (ret)
1178 		return ret;
1179 
1180 	wait_event_timeout(mhi_cntrl->state_event,
1181 			   MHI_IN_MISSION_MODE(mhi_cntrl->ee) ||
1182 			   MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state),
1183 			   msecs_to_jiffies(mhi_cntrl->timeout_ms));
1184 
1185 	ret = (MHI_IN_MISSION_MODE(mhi_cntrl->ee)) ? 0 : -ETIMEDOUT;
1186 	if (ret)
1187 		mhi_power_down(mhi_cntrl, false);
1188 
1189 	return ret;
1190 }
1191 EXPORT_SYMBOL(mhi_sync_power_up);
1192 
1193 int mhi_force_rddm_mode(struct mhi_controller *mhi_cntrl)
1194 {
1195 	struct device *dev = &mhi_cntrl->mhi_dev->dev;
1196 	int ret;
1197 
1198 	/* Check if device is already in RDDM */
1199 	if (mhi_cntrl->ee == MHI_EE_RDDM)
1200 		return 0;
1201 
1202 	dev_dbg(dev, "Triggering SYS_ERR to force RDDM state\n");
1203 	mhi_set_mhi_state(mhi_cntrl, MHI_STATE_SYS_ERR);
1204 
1205 	/* Wait for RDDM event */
1206 	ret = wait_event_timeout(mhi_cntrl->state_event,
1207 				 mhi_cntrl->ee == MHI_EE_RDDM,
1208 				 msecs_to_jiffies(mhi_cntrl->timeout_ms));
1209 	ret = ret ? 0 : -EIO;
1210 
1211 	return ret;
1212 }
1213 EXPORT_SYMBOL_GPL(mhi_force_rddm_mode);
1214 
1215 void mhi_device_get(struct mhi_device *mhi_dev)
1216 {
1217 	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
1218 
1219 	mhi_dev->dev_wake++;
1220 	read_lock_bh(&mhi_cntrl->pm_lock);
1221 	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state))
1222 		mhi_trigger_resume(mhi_cntrl);
1223 
1224 	mhi_cntrl->wake_get(mhi_cntrl, true);
1225 	read_unlock_bh(&mhi_cntrl->pm_lock);
1226 }
1227 EXPORT_SYMBOL_GPL(mhi_device_get);
1228 
1229 int mhi_device_get_sync(struct mhi_device *mhi_dev)
1230 {
1231 	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
1232 	int ret;
1233 
1234 	ret = __mhi_device_get_sync(mhi_cntrl);
1235 	if (!ret)
1236 		mhi_dev->dev_wake++;
1237 
1238 	return ret;
1239 }
1240 EXPORT_SYMBOL_GPL(mhi_device_get_sync);
1241 
1242 void mhi_device_put(struct mhi_device *mhi_dev)
1243 {
1244 	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
1245 
1246 	mhi_dev->dev_wake--;
1247 	read_lock_bh(&mhi_cntrl->pm_lock);
1248 	if (MHI_PM_IN_SUSPEND_STATE(mhi_cntrl->pm_state))
1249 		mhi_trigger_resume(mhi_cntrl);
1250 
1251 	mhi_cntrl->wake_put(mhi_cntrl, false);
1252 	read_unlock_bh(&mhi_cntrl->pm_lock);
1253 }
1254 EXPORT_SYMBOL_GPL(mhi_device_put);
1255